North Korea "best not make any more threats to the United States" or it will "be met with fire and fury like the world has never seen," Trump said at the time, according to press pool reports.

Responding to Trump's latest comments at the UN during which he accused Kim Jong Un of being on "a suicide mission," North Korea's foreign minister said that "none other than Trump himself is on a suicide mission," and added that if American civilians are hurt by suicide attacks, "Trump will be held totally responsible."

Kim also lashed out at Trump following the UN speech."I will surely and definitely tame the mentally deranged U.S. dotard with fire," the North Korean leader said on Thursday, according to The Associated Press.

And after Trump issued an executive order imposing new sanctions on North Korea, Kim responded by saying the US would "pay dearly" for the new sanctions.

Trump retaliated by calling Kim a "madman" who would "be tested like never before" in a Friday morning tweet.

On Monday, the White House also announced that Trump and Chinese president Xi Jinping have agreed on "maximizing pressure" on North Korea.